Research on extraction of alumina from red mud by sintering process with circulating spent liquor addition
In order to address the problems of high carbon emission and high production cost of lime-soda sintering process for treating red mud,a novel process to extract alumina from red mud by the sintering process with the addition of circulating spent liquor is proposed.Effects of different ratios of circu-lating spent liquor to sodium carbonate on the sintering properties and leaching properties of clinker as well as the settleability of leaching slurry are stud-ied.The results show that the main phases of the sintered clinker produced by using circulating spent liquor as alkali source are Na2O·Al2O3,2CaO·SiO2,2CaO·Fe2O3 and CaO·TiO2.Increasing the ratio of circulating spent liquor can improve the leaching rate of Al2O3 and Na2O.At the same time,the circulating spent liquor is used as alkali source to convert Fe2O3 into 2CaO·Fe2O3,and the settleability of leaching slurry can be im-proved as a result.Under the condition of using circulating spent liquor as alkali source,the carbon dioxide emissions during the sintering process of clink-er are significantly reduced,the actual leaching rates of clinker Al2O3 and Na2O are above 89％and 96％,the settling rate of the leaching slurry and the compressibility of the mud layer can reach 10.55 m/h and 76％,respectively.
red mudlow-carbon sinteringaluminaleachingsettlement
万方数据
维普
